A laser source pump is a device to generate coherent light for use by various systems. Laser pumping is the act of energy transfer from an external source into the gain medium of a laser, wherein energy is absorbed in the medium, producing excited states in its atoms. When the number of particles in one excited state exceeds the number of particles in the ground state or a less-excited state, population inversion is achieved. In this condition, the mechanism of stimulated emission can take place and the medium can act as a laser or an optical amplifier. The pump energy is usually provided in the form of light or electric current.
Such laser pump sources are often utilized in accordance with a gyroscope for positioning systems, for example. A major requirement for such lasers is to be able to generate a consistent wavelength over a vast temperature range (e.g., −60 to 90 deg C.). Past attempts at achieving such stability have involved the use of polarization-maintaining (PM) optical fiber that was excited by a laser diode. The PM fiber was difficult to stabilize however as multiple propagation modes could be launched in the fiber that cause transmission inefficiencies.